This large monograph summarizes, primarily, morphologic observations in 23 patients with infective endocarditis involving right-sided cardiac valves with or without involvement of left-sided valves, 74 patients with infective endocarditis limited at left-sided cardiac valves, 22 patients with prosthetic operations, 6 patients with infective endocarditis complicating congenital cardiac disease with a shunt, and 8 with infective endocarditis limited to mural endocardium. It is clear that in the past decade infective endocarditis is far more common on previously normal valves both anatomically and functionally than on previously abnormal valves.